US bombers have been flying missions over the western Pacific since 2004.

The missions, part of the Continuous Bomber Presence, are meant to reassure allies and send a message to rivals.

The missions have continued amid growing tensions with China.

US bombers have been plying the skies over the western Pacific since 2004, seeking to bolster allies in response to concerns about rival powers in the region.

US Air Force B-52s, B-1s, and B-2s are still flying out of Anderson Air Force Base in Guam to maintain the Continuous Bomber Presence, as it is known, patrolling around the Korean Peninsula and the South China Sea to build readiness and let allies and rivals alike know that the US is watching the region. The B-52 and B-2 are capable of carrying nuclear weapons on patrols.

"What it does do, aside from building readiness, is it assures partners and allies that we are in the Pacific [area of responsibility] in support of them," Maj. Gen. Russell L. Mack, deputy commander of Pacific Air Forces, told Brian Everstine of Air Force Magazine, who recently accompanied a B-52 crew on a mission in the area.

"Everybody loves the B-52," Lt. Col. Jerred Prier, director of operations for the 20th Expeditionary Bomb Squadron, told Everstine. The bomber "is one of the most recognizable airplanes in the world; it carries a lot of different weapons types. Both partners and allies recognize it."

Below, you can step aboard a B-52 as it carries out a recent training mission near Guam.

CBP flights frequently take US aircraft over the South China Sea, where Beijing has made expansive claims that several other countries dispute. China has also built up its presence there, constructing artificial islands on which it has put military bases and equipment.

Those bases extend the range of Chinese bombers, though they are still limited by their inability to refuel while in flight.

The US has continued its CBP missions in the area, working to preserve freedom of navigation at sea and in the air. In April, two B-52s left Guam and reportedly flew within 155 miles of Guangdong province in southeast China.

That flight reportedly brought the bombers within cruise-missile range of China but put them within range of Chinese radar and weapons systems. Pacific Air Forces said at the time that the flight was routine, though other reports said it was rare for US bombers to fly so close to the Chinese coast.

CBP flights appear to have picked up in the months since — including several flights over the South China Sea during the final days of August — earning reproach from Beijing, which this summer accused the US of "running amok" in the region.

"Ultimately, it increased our readiness to serve as a credible deterrent force and presence within the theater," Maj. John Radtke, mission planner for the 96th Expeditionary Bomber Squadron, told Business Insider of the August missions.

Mack, the deputy commander of Pacific Air Forces, told Everstine his current deployment to the Pacific was bigger than his last tour there, which ended in 2015.

China "has expanded their capability, expanded their military … they're expanding their horizons," Mack said. "They've watched us for the past three decades," he added. "They know how the US likes to fight."